protocol.c

非常不错的网管开发包

#include <config.h>

#include <stdio.h>
#include <errno.h>
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/types.h>
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
#  include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

#if HAVE_WINSOCK_H
#include <winsock.h>
#endif

#include "asn1.h"
#include "snmp_api.h"
#include "snmp_impl.h"
#include "snmp.h"
#include "snmp_client.h"
#include "snmp_debug.h"
#include "mib.h"

#include "agentx/protocol.h"

int agentx_dump(struct snmp_session *,struct snmp_pdu *, u_char *, size_t);

void
agentx_build_int(u_char *bufp, u_int value, int network_byte_order)
{
    if ( network_byte_order ) {
#ifndef WORDS_BIGENDIAN
	value = ntohl( value );
#endif
	memmove( bufp, &value, 4);
    }
    else {
#ifndef WORDS_BIGENDIAN
	memmove( bufp, &value, 4);
#else
	*bufp = (u_char)value & 0xff;	value >>=8;	bufp++;
	*bufp = (u_char)value & 0xff;	value >>=8;	bufp++;
	*bufp = (u_char)value & 0xff;	value >>=8;	bufp++;
	*bufp = (u_char)value & 0xff;
#endif
    }
}

void
agentx_build_short(u_char *bufp, int in_value, int network_byte_order)
{
    u_short value = (u_short)in_value;
    if ( network_byte_order ) {
#ifndef WORDS_BIGENDIAN
	value = ntohs( value );
#endif
	memmove( bufp, &value, 2);
    }
    else {
#ifndef WORDS_BIGENDIAN
	memmove( bufp, &value, 2);
#else
	*bufp = (u_char)value & 0xff;	value >>=8;	bufp++;
	*bufp = (u_char)value & 0xff;
#endif
    }
}


u_char*
agentx_build_oid(u_char *bufp, size_t *out_length, int inc,
	oid *name, size_t name_len, int network_byte_order)
{
    int prefix = 0;
    size_t i;

    if ( name_len == 2 && name[0]  == 0 && name[1]  == 0  ) {
	 name_len = 0;	/* NUll OID */
    }
    
    	/* 'Compact' internet OIDs */
    if ( name_len >= 5 &&
	 name[0] == 1 && name[1] == 3 &&
         name[2] == 6 && name[3] == 1 ) {
	 
	 prefix = name[4];
	 name += 5;
	 name_len -= 5;
    }
    
    if ( *out_length < 4 + 4*name_len )
        return NULL;

    *bufp = (u_char)name_len;	bufp++;
    *bufp = (u_char)prefix;	bufp++;
    *bufp = (u_char)inc;	bufp++;
    *bufp = 0;			bufp++;
    *out_length -= 4;
    
    for ( i = 0 ; i < name_len ; i++ ) {
        agentx_build_int( bufp, name[i], network_byte_order );
	bufp        += 4;
	*out_length -= 4;
    }

    return bufp;
}

u_char*
agentx_build_string(u_char *bufp, size_t *out_length,
	u_char *name, size_t name_len, int network_byte_order)
{
    if ( *out_length < 4 + name_len ) {
        return NULL;
    }
    agentx_build_int( bufp, (u_int)name_len, network_byte_order );
    bufp        += 4;
    *out_length -= 4;
    if ( name_len == 0 )
	return bufp;
    
    memmove( bufp, name, name_len );
    bufp        +=  name_len;
    *out_length -= name_len;    
    
    	/* Pad to a multiple of 4 bytes */
    name_len &= 0x3;
    if ( name_len )
	name_len = 4-name_len; 
    for ( ; name_len ; name_len-- ) {
	*bufp = 0;
	bufp++;
	*out_length--;
    }
    return bufp;
}

u_char*
agentx_build_varbind(u_char *bufp, size_t *out_length,
	struct variable_list *vp, int network_byte_order)
{
    if ( *out_length < 4 )
    	return NULL;
	
    agentx_build_short( bufp, (u_int)vp->type, network_byte_order);
    bufp        +=2;
    *bufp = 0;			bufp++;
    *bufp = 0;			bufp++;		/* <reserved> */
    *out_length -=4;

    bufp = agentx_build_oid( bufp, out_length, 0,
	    		vp->name, vp->name_length, network_byte_order);
    if ( bufp == NULL )
    	return NULL;

    switch ( (short)vp->type ) {
    
  	case ASN_INTEGER:
	case ASN_COUNTER:
	case ASN_GAUGE:
	case ASN_TIMETICKS:
		if ( *out_length < 4 )
		    return NULL;
		agentx_build_int( bufp, *(vp->val.integer), network_byte_order);
		bufp        += 4;
		*out_length -= 4;
		break;

	case ASN_OCTET_STR:
	case ASN_IPADDRESS:
	case ASN_OPAQUE:
		bufp = agentx_build_string( bufp, out_length,
	    		vp->val.string, vp->val_len, network_byte_order);
		break;
		
	case ASN_OBJECT_ID:
		bufp = agentx_build_oid( bufp, out_length, 0,
	    		vp->val.objid, vp->val_len/4, network_byte_order);
		break;

	case ASN_COUNTER64:
		if ( *out_length < 8 )
		    return NULL;
		if ( network_byte_order ) {
		    agentx_build_int( bufp, vp->val.counter64->high, network_byte_order);
		    agentx_build_int( bufp+4, vp->val.counter64->low,  network_byte_order);
		}
		else {
		    agentx_build_int( bufp, vp->val.counter64->low,  network_byte_order);
		    agentx_build_int( bufp+4, vp->val.counter64->high, network_byte_order);
		}
		bufp        += 8;
		*out_length -= 8;
		break;

   	case ASN_NULL:
	case SNMP_NOSUCHOBJECT:
	case SNMP_NOSUCHINSTANCE:
	case SNMP_ENDOFMIBVIEW:
		break;

	default:
		return NULL;
    }
    return bufp;
}

u_char*
agentx_build_header(struct snmp_pdu *pdu, u_char *bufp, size_t *out_length)
{

    *bufp = 1;			bufp++;		/* version */
    *bufp = pdu->command;	bufp++;		/* type    */
    *bufp = pdu->flags & AGENTX_MSG_FLAGS_MASK;
    				bufp++;		/* AgentX flags */
    *bufp = 0;			bufp++;		/* <reserved> */
    *out_length -=4;
    
    agentx_build_int( bufp, pdu->sessid, pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
    *out_length -=4;
    bufp        +=4;
    agentx_build_int( bufp, pdu->transid,  pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
    *out_length -=4;
    bufp        +=4;
    agentx_build_int( bufp, pdu->reqid,  pdu->flags & AGENTX_FLAGS_NETWORK_BYTE_ORDER );
    *out_length -=4;
    bufp        +=4;
    agentx_build_int( bufp, 0, 0 );  /* dummy payload length */
    *out_length -=4;
    bufp        +=4;

    if ( pdu->flags & AGENTX_MSG_FLAG_NON_DEFAULT_CONTEXT ) {
	bufp = agentx_build_string( bufp, out_length,
		pdu->community,
		pdu->community_len,
		pdu->flags & AGENTX_MSG_FLAG_NETWORK_BYTE_ORDER );
    }
		
    return bufp;
}


static int
_agentx_build(struct snmp_session        *session,
             struct snmp_pdu            *pdu,
             register u_char            *packet,
             size_t                        *out_length)
{
     u_char *bufp = packet;
     u_char *prefix_ptr, *range_ptr;
     size_t length;
     struct variable_list *vp;
     int inc;
     
    session->s_snmp_errno = 0;
    session->s_errno = 0;
     
		/* Build the header (and context if appropriate) */
     if ( *out_length < 20 )
	        return -1;
     bufp = agentx_build_header( pdu, bufp, out_length );
     if ( bufp == NULL )
     	return -1;
     
     switch ( pdu->command ) {
     	case AGENTX_MSG_OPEN:
			/* Timeout */
	    if ( *out_length < 4 )
	        return -1;
	    *bufp = pdu->time;		bufp++;
	    *bufp = 0;			bufp++;
	    *bufp = 0;			bufp++;
	    *bufp = 0;			bufp++;
	    *out_length -= 4;

	    bufp = agentx_build_oid( bufp, out_length, 0,
	    		pdu->variables->name, pdu->variables->name_length,
			pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    if ( bufp == NULL )
	    	return -1;
	    bufp = agentx_build_string( bufp, out_length,
	    		pdu->variables->val.string, pdu->variables->val_len,
			pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    if ( bufp == NULL )
	    	return -1;
	    break;
	    
	case AGENTX_MSG_CLOSE:
			/* Reason */
	    if ( *out_length < 4 )
	        return -1;
	    *bufp = pdu->errstat;	bufp++;
	    *bufp = 0;			bufp++;
	    *bufp = 0;			bufp++;
	    *bufp = 0;			bufp++;
	    *out_length -= 4;
	    break;
	    
	case AGENTX_MSG_REGISTER:
	case AGENTX_MSG_UNREGISTER:
	    if ( *out_length < 4 )
	        return -1;
	    *bufp = pdu->time;		bufp++;	    /* Timeout (Register only) */
	    *bufp = pdu->priority;		bufp++;
	    range_ptr = bufp;	 	/* Points to the 'range_subid' field */
	    *bufp = pdu->range_subid;	bufp++;
	    *bufp = 0;			bufp++;
	    *out_length -= 4;

	    vp = pdu->variables;
	    prefix_ptr = bufp+1;	/* Points to the 'prefix' field */
	    bufp = agentx_build_oid( bufp, out_length, 0,
	    		vp->name, vp->name_length,
			pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    if ( bufp == NULL )
	    	return -1;


	    if ( pdu->range_subid ) {
		if ( *out_length < 4 )
		    return -1;

			/* This assumes that the two OIDs match
			     to form a valid range */
	    	agentx_build_int( bufp, vp->val.objid[pdu->range_subid-1],
					pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
		bufp        += 4;
		*out_length -= 4;

			/* If the OID has been 'compacted', then tweak
			     the packet's 'range_subid' to reflect this */
		if ( *prefix_ptr )
		     *range_ptr -= 5;
	    }
	    break;
	    
	case AGENTX_MSG_GETBULK:
	    if ( *out_length < 4 )
	        return -1;
	    agentx_build_short( bufp  , pdu->non_repeaters,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    agentx_build_short( bufp+2, pdu->max_repetitions,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    bufp        += 4;
	    *out_length -= 4;

		/* Fallthrough */

	case AGENTX_MSG_GET:
	case AGENTX_MSG_GETNEXT:

	    for (vp = pdu->variables; vp ; vp=vp->next_variable ) {
	        inc = ( vp->type == ASN_PRIV_INCL_RANGE );
		bufp = agentx_build_oid( bufp, out_length, inc,
	    		vp->name, vp->name_length,
			pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    	if ( bufp == NULL )
	    	    return -1;
		bufp = agentx_build_oid( bufp, out_length, 0,
	    		vp->val.objid, vp->val_len/4,
			pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    	if ( bufp == NULL )
	    	    return -1;
	    }
	    break;

	case AGENTX_MSG_RESPONSE:
	    pdu->flags &= ~(UCD_MSG_FLAG_EXPECT_RESPONSE);
	    if ( *out_length < 4 )
	        return -1;
	    agentx_build_int( bufp, pdu->time,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    bufp        += 4;
	    *out_length -= 4;

	    if ( *out_length < 4 )
	        return -1;
	    agentx_build_short( bufp  , pdu->errstat,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    agentx_build_short( bufp+2, pdu->errindex,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    bufp        += 4;
	    *out_length -= 4;

		/* Fallthrough */

	case AGENTX_MSG_INDEX_ALLOCATE:
	case AGENTX_MSG_INDEX_DEALLOCATE:
	case AGENTX_MSG_NOTIFY:
	case AGENTX_MSG_TESTSET:
	    for (vp = pdu->variables; vp ; vp=vp->next_variable ) {
		bufp = agentx_build_varbind( bufp, out_length, vp,
				pdu->flags &  AGENTX_FLAGS_NETWORK_BYTE_ORDER);
	    	if ( bufp == NULL )
	    	    return -1;
	    }
	    break;
	    
	case AGENTX_MSG_COMMITSET:
	case AGENTX_MSG_UNDOSET:
	case AGENTX_MSG_CLEANUPSET:
	case AGENTX_MSG_PING: